Solid-state imaging device, method for manufacturing solid-state imaging device and electronic apparatus

ABSTRACT

Provided are a solid-state imaging device, a method for manufacturing a solid-state imaging device and an electronic apparatus that produce little crosstalk between adjacent sub-pixels, can reduce the influence of the luminance shading, and can even prevent degradation in the sensitivity at the optical center. A multi-pixel includes a back-side separating part separating a plurality of adjacent sub-pixels from each other, and a lens part including a single microlens allowing light to enter photoelectric converting regions of sub-pixels. Here, the optical center of the microlens is positioned on the location where the back side separating part is formed, and the back side separating part is formed such that at least the optical center region thereof exhibits lower reflection than the other region of the back side separating part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority fromJapanese Patent Application Serial No. 2019-117321 (filed on Jun. 25,2019), the contents of which are hereby incorporated by reference intheir entirety.

TECHNICAL FIELD

The present invention relates to a solid-state imaging device, a methodfor manufacturing a solid-state imaging device, and an electronicapparatus.

BACKGROUND

Solid-state imaging devices (image sensors) including photoelectricconversion elements for detecting light and generating charges areembodied as CMOS (complementary metal oxide semiconductor) imagesensors, which have been in practical use. The CMOS image sensors havebeen widely applied as parts of various types of electronic apparatusessuch as digital cameras, video cameras, surveillance cameras, medicalendoscopes, personal computers (PCs), mobile phones and other portableterminals (mobile devices).

A common CMOS image sensor captures color images using three primarycolor filters for red (R), green (G), and blue (B) or four complementarycolor filters for cyan, magenta, yellow, and green.

In general, each pixel in a CMOS image sensor has one or more filters.The filters are arranged such that four filters including a red (R)filter that mainly transmits red light, green (Gr, Gb) filters thatmainly transmit green light, and a blue (B) filter that mainly transmitsblue light are arranged in a square geometry and forms a group ofsub-pixels referred to as a unit RGB sub-pixel group or multi-pixel andthat the multi-pixels are arranged two-dimensionally.

Light incident on the CMOS image sensor goes through the filters beforereceived by photodiodes. The photodiodes receive light havingwavelengths (380 nm to 1,100 nm) within a region wider than the regionof wavelengths visible to the human eye (380 nm to approximately 780 nm)and produce signal charges. Therefore, the photodiodes may suffer fromerrors produced by infrared light and thus have reduced colorreproduction quality. Accordingly, it is a general practice to eliminateinfrared light previously by infrared cut filters (IR cut filters).However, the IR cut filters attenuate visible light by approximately 10%to 20%, resulting in reduced sensitivity of the solid-state imagingdevice and degraded image quality.

To overcome this problem, a CMOS image sensor (a solid-state imagingdevice) can be realized without the use of IR cut filters and has beendevised (see, for example, Japanese Patent Application Publication No.2017-139286). This CMOS image sensor includes sub-pixel groups arrangedtwo-dimensionally, and the sub-pixel groups are unit RGBIR sub-pixelgroups or multi-pixels. Each sub-pixel group includes sub-pixelsarranged in a square geometry, that is, an R sub-pixel including a red(R) filter that mainly transmits red light, a G sub-pixel including agreen (G) filter that mainly transmits green light, a B sub-pixelincluding a blue (B) filter that mainly transmits blue light, and one ofa near-infrared (NIR, for example, 850 nm, 940 nm) dedicated sub-pixelthat receives infrared light and a monochrome infrared (M-NIR, forexample, 500 nm to 955 nm) sub-pixel that receives monochrome (M) lightand infrared light. When the NIR sub-pixel is present, the filter cancut off IR at a selected wavelength or pass IR within a predeterminedwavelength range. When configured to cut off the IR, the filter blockslight of the designated wavelength from entering the image sensor. Whenconfigured to pass the IR, the filter passes only the IR light withinthe selected wavelength range. Every sub-pixel in the multi-pixel canhave one or more on-chip color filter layers. For example, a sub-pixelcan have a double-layered color filter structure formed by combiningtogether an NIR filter that cuts off or passes the IR at a specificwavelength or within a specific wavelength range and an R, G or B layer.This CMOS image sensor operates as a NIR-RGB sensor that can captureso-called NIR images and RGB images.

In this CMOS image sensor, output signals from sub-pixels receivinginfrared light are used to correct output signals from sub-pixelsreceiving red, green, and blue light, thereby achieving high colorreproducibility without the use of IR cut filters.

Further, there has been known an infrared (IR, NIR) sensor in which thefour sub-pixels in a unit sub-pixel group or multi-pixel are replacedwith one NIR pixel having a larger pixel size and dedicated to receiveNIR.

FIGS. 1A to 1C schematically show a first example configuration of asolid-state imaging device (a CMOS image sensor) having a microlens foreach sub-pixel. FIG. 1A is a plan view schematically showing an examplearrangement of constituents of a solid-state imaging device (a CMOSimage sensor) formed as an NIR-RGB sensor. FIG. 1B is a simplifiedsectional view along the line x1-x2 in FIG. 1A. FIG. 1C is a simplifiedsectional view along the line y1-y2 in FIG. 1A.

In the solid-state imaging device 1 shown in FIGS. 1A to 1C, amulti-pixel MPXL1 is constructed such that a G sub-pixel SPXLG with agreen (G) filter FLT-G that mainly transmits green light, an R sub-pixelSPXLR with a red (R) filter FLT-R that mainly transmits red light, a Bsub-pixel SPXLB with a blue (B) filter FLT-B that mainly transmits bluelight and a dedicated near-infrared (NIR) sub-pixel SPXLNI that receivesinfrared light are arranged in two rows and two columns in a squaregeometry.

In the multi-pixel MPXL1, an anti-reflective film ARL is formed betweenthe light entering surface of photoelectric converting region PD (1-4)and the light exiting surface of the filters. The light entering portionof the photoelectric converting region PD of the multi-pixel MPXL1 isdivided (segmented) into a first photoelectric converting region PD1, asecond photoelectric converting region PD2, a third photoelectricconverting region PD3 and a fourth photoelectric converting region PD4,which respectively correspond to the sub-pixels SPXLG, SPXLR, SPXLB,SPXLNI. More specifically, the light entering portion of thephotoelectric converting region PD is divided into four portions by aback side metal (BSM), which serves as a back-side separating part. Inthe example shown in FIGS. 1A to 1C, the back side metal BSM is formedat the boundaries between the sub-pixels SPXLG, SPXLR, SPXLB, and SPXLNIsuch that the back side metal BCM protrudes from the anti-reflectivefilm ARL into the filters. Additionally, in the photoelectric convertingregion PD, a back side deep trench isolation (BDTI) is formed as atrench-shaped back side separation such that the BDTI is aligned withthe back side metal (BSM) in the depth direction of the photoelectricconverting region PD. In this way, the sub-pixel SPXLG includes thefirst photoelectric converting region PD1, the sub-pixel SPXLR includesthe second photoelectric converting region PD2, the sub-pixel SPXLBinclude the third photoelectric converting region PD3, and the sub-pixelSPXLNI includes the fourth photoelectric converting region PD4.

In the solid-state imaging device 1, the sub-pixel regions have, at thelight entering side of the filter, corresponding microlenses MCL1, MCL2,MCL3 and MCL4. The microlens MCL1 allows light to enter the firstphotoelectric converting region PD1 of the sub-pixel SPXLG, themicrolens MCL2 allows light to enter the second photoelectric convertingregion PD2 of the sub-pixel SPXLR, the microlens MCL3 allows light toenter the third photoelectric converting region PD3 of the sub-pixelSPXLB, and the microlens MCL4 allows light to enter into the fourthphotoelectric converting region PD4 of the sub-pixel SPXLNI.

FIGS. 2A and 2B schematically show second and third exampleconfigurations of a solid-state imaging device (CMOS image sensor) whereeach sub-pixel has a microlens. FIG. 2A is a plan view schematicallyshowing an example arrangement of constituents of a solid-state imagingdevice (a CMOS image sensor) formed as an RGB sensor. FIG. 2B is a planview schematically showing an example arrangement of constituents of asolid-state imaging device (a CMOS image sensor) formed as an M-NIRsensor.

When a multi-pixel MPXL1A of a solid-state imaging device 1A shown inFIG. 2A is compared with the multi-pixel MPXL1 of FIGS. 1A to 1C, thenear infrared (NIR) sub-pixel SPXLNI is replaced with a G sub-pixelSPXLG.

In a multi-pixel MPXL1B of a solid-state imaging device 1B shown in FIG.2B, the G sub-pixel SPXLG and the R sub-pixel SPCLR in the same row arereplaced with an M sub-pixel SPXLM and a single microlens MCL5. The Bsub-pixel SPXLB is replaced with an NIR sub-pixel SPXLNI covering twosub-pixel regions and with a single microlens MCL6.

FIGS. 3A to 3C schematically show a fourth example configuration of asolid-state imaging device (a CMOS image sensor) in which one microlensis shared between a plurality of sub-pixels. FIG. 3A is a plan viewschematically showing an example arrangement of constituents of asolid-state imaging device (a CMOS image sensor) formed as an NIR-RGBsensor. FIG. 3B is a simplified sectional view along the line x1-x2 inFIG. 3A. FIG. 3C is a simplified sectional view along the line y1-y2 inFIG. 3A.

In a multi-pixel MPXL1C of a solid-state imaging device 1C shown in FIG.3A, four sub-pixels SPXLG, SPXLR, SPXLB and SPXLNI that are arranged ina square geometry of 2×2 share a single microlens MCL7.

FIGS. 4A and 4B schematically show fifth and sixth exampleconfigurations of a solid-state imaging device (a CMOS image sensor) inwhich a plurality of sub-pixels share a single microlens. FIG. 4A is aplan view schematically showing an example arrangement of constituentsof a solid-state imaging device (a CMOS image sensor) formed as an RGBsensor. FIG. 4B is a plan view schematically showing as an examplearrangement of constituents of a solid-state imaging device (a CMOSimage sensor) formed as an M-NIR sensor.

In a multi-pixel MPXL1D of a solid-state imaging device 1D shown in FIG.4A, four sub-pixels SPXLG, SPXLR, SPXLB and SPXLG that are arranged in asquare geometry of 2×2 share a single microlens MCL8.

In a multi-pixel MPXL1E of a solid-state imaging device 1E shown in FIG.4B, two sub-pixels SPXLM and SPXLNI share a single microlens MCL9.

The solid-state imaging devices (CMOS image sensors) where eachsub-pixel has a microlens, as shown in FIGS. 1A to 1C and FIGS. 2A and2B, have the following advantages and disadvantages.

<Advantages>

Little crosstalk occurs between adjacent sub-pixels. Since the opticalcenter of the microlens coincides with the optical center of thephotoelectric converting region (photodiode) PD, symmetrical luminanceshading can be achieved.

<Disadvantages>

The responsiveness is low due to the gap between different microlenses.As no distance information can be obtained, phase detection auto focus(PDAF) capability can never be provided.

The solid-state imaging devices (CMOS image sensors) shown in FIGS. 3Ato 3C and FIGS. 4A and 4B, where a plurality of sub-pixels share asingle microlens, have the following advantages and disadvantages.

<Advantages>

Every pixel can have distance information, which can be applied toprovide for the PDAF capability.

<Disadvantages>

Since each pixel has a different shading profile, the luminance shadingwields a significant impact. As the optical center of the microlens ispositioned at the location where the back side metal (BSM) is formed,reflection and the like radically lowers the sensitivity at the opticalcenter.

SUMMARY

One object of the present invention is to provide a solid-state imagingdevice, a method for manufacturing a solid-state imaging device, and anelectronic apparatus that produces little crosstalk between adjacentsub-pixels, can reduce the influence of the luminance shading, and caneven prevent the degradation in the sensitivity at the optical center.

A first aspect of the present invention provides a solid-state imagingdevice including a multi-pixel including at least two sub-pixels, whereeach sub-pixel has a photoelectric converting region. The multi-pixelincludes a back side separating part separating a plurality of adjacentsub-pixels from each other at least in a light entering portion of thephotoelectric converting region thereof, and a single lens part allowinglight to enter a photoelectric converting region of at least twosub-pixels. The lens part is arranged such that an optical centerthereof is positioned at a location where the back side separating partis formed. The back side separating part is formed such that at least anoptical center region thereof exhibits lower reflection than the otherregion of the back side separating part.

A second aspect of the present invention provides a method formanufacturing a solid-state imaging device including a multi-pixelhaving at least two sub-pixels, where each sub-pixel has a photoelectricconverting region. The multi-pixel has a back side separating partseparating a plurality of adjacent sub-pixels from each other at leastin a light entering portion of the photoelectric converting regionthereof, and a single lens part allowing light to enter a photoelectricconverting region of at least two sub-pixels. An optical center of thelens part is positioned at a location where the back side separatingpart is formed. The back side separating part is formed such that atleast an optical center region thereof exhibits lower reflection thanthe other region of the back side separating part.

A third aspect of the present invention provides an electronic apparatusincluding a solid-state imaging device and an optical system for forminga subject image on the solid-state imaging device. The solid-stateimaging device includes a multi-pixel having at least two sub-pixels,where each sub-pixel has a photoelectric converting region. Themulti-pixel has a back side separating part separating a plurality ofadjacent sub-pixels from each other at least in a light entering portionof the photoelectric converting region and a single lens part allowinglight to enter a photoelectric converting region of at least twosub-pixels. The lens part is arranged such that an optical centerthereof is positioned at a location where the back side separating partis formed. The back side separating part is formed such that at least anoptical center region thereof exhibits lower reflection than the otherregion of the back side separating part.

Advantageous Effects

The present invention produces little crosstalk between adjacentsub-pixels, can reduce the influence of the luminance shading, and caneven prevent the degradation in the sensitivity at the optical center.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C schematically show a first example configuration of asolid-state imaging device (a CMOS image sensor) where each sub-pixelhas a microlens.

FIGS. 2A and 2B schematically show second and third exampleconfigurations of a solid-state imaging device (a CMOS image sensor)where each sub-pixel has a microlens.

FIGS. 3A to 3C schematically show a fourth example configuration of asolid-state imaging device (a CMOS image sensor) where a plurality ofsub-pixels share a single microlens.

FIGS. 4A and 4B schematically show fifth and sixth exampleconfigurations of a solid-state imaging device (a CMOS image sensor)where a plurality of sub-pixels share a single microlens.

FIG. 5 is a block diagram showing an example configuration of asolid-state imaging device according to a first embodiment of thepresent invention.

FIG. 6 is a circuit diagram showing an example multi-pixel, where foursub-pixels share a single floating diffusion, in a pixel part of thesolid-state imaging device according to the first embodiment of thepresent invention.

FIGS. 7A to 7C show example configurations of a column signal processingcircuit in a reading circuit according to the embodiment.

FIGS. 8A to 8C schematically show an example configuration of thesolid-state imaging device (the CMOS image sensor) according to thefirst embodiment of the present invention.

FIGS. 9A to 9C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a secondembodiment of the present invention.

FIGS. 10A to 10C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a thirdembodiment of the present invention.

FIGS. 11A to 11C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a fourthembodiment of the present invention.

FIGS. 12A to 12C schematically show a modification example of thesolid-state imaging device (the CMOS image sensor) according to thefourth embodiment of the present invention.

FIGS. 13A to 13C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a fifthembodiment of the present invention.

FIGS. 14A to 14C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a sixthembodiment of the present invention.

FIG. 15 schematically shows an example configuration of a solid-stateimaging device (a CMOS image sensor) according to a seventh embodimentof the present invention.

FIG. 16 schematically shows a modification example of the solid-stateimaging device (the CMOS image sensor) according to the seventhembodiment of the present invention.

FIG. 17 shows an example configuration of an electronic apparatus towhich the solid-state imaging devices relating to the embodiments of thepresent invention can be applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be hereinafter described withreference to the drawings.

First Embodiment

FIG. 5 is a block diagram showing an example configuration of asolid-state imaging device relating to a first embodiment of the presentinvention. In this embodiment, a solid-state imaging device 10 isconstituted by, for example, a CMOS image sensor. The CMOS image sensoris, for example, applied to back-side illumination image sensor (BSI).

As shown in FIG. 5, the solid-state imaging device 10 is constitutedmainly by a pixel part 20 serving as an image capturing part, a verticalscanning circuit (a row scanning circuit) 30, a reading circuit (acolumn reading circuit) 40, a horizontal scanning circuit (a columnscanning circuit) 50, and a timing control circuit 60. Among thesecomponents, for example, the vertical scanning circuit 30, the readingcircuit 40, the horizontal scanning circuit 50, and the timing controlcircuit 60 constitute the reading part 70 for reading out pixel signals.

In the solid-state imaging device 10 relating to the first embodiment,as will be described in detail below, the pixels arranged in a matrixpattern in the pixel part 20 are each a multi-pixel constituted by atleast two (four, in the first embodiment) sub-pixels each having aphotoelectric converting region. In the first embodiment, themulti-pixel includes a back side separating part separating a pluralityof adjacent sub-pixels from each other at least in a light enteringportion of the photoelectric converting region of the multi-pixel and asingle lens part allowing light to enter the photoelectric convertingregions of at least two sub-pixels. In the first embodiment, the opticalcenter of the lens part is positioned at the location where the backside separating part is formed, and at least the optical center regionof the back side separating part exhibits lower reflection (higherabsorption) than the other region of the back side separating part. Inthe first embodiment, the optical center region of the back sideseparating part exhibits lower reflection (higher absorption) than theother region of the back side separating part.

In the first embodiment, the multi-pixel serves as a unit group ofsub-pixels and is configured as an NIR-RGB sensor.

The following briefly describes the configurations and functions of theparts of the solid-state imaging device 10 and then describes in detailthe configurations and arrangement of the multi-pixels.

<Configuration of Pixel Part 20 and Multi-Pixel MPXL20>

In the pixel part 20, a plurality of multi-pixels each including aphotodiode (a photoelectric conversion part) and an in-pixel amplifierare arranged in a two-dimensional matrix comprised of N rows and Mcolumns.

FIG. 6 is a circuit diagram showing an example multi-pixel in which foursub-pixels share a single floating diffusion in the pixel part of thesolid-state imaging device relating to the first embodiment of thepresent invention.

In the pixel part 20 of FIG. 6, a multi-pixel MPXL20 has foursub-pixels, namely, a first sub-pixel SPXL11, a second sub-pixel SPXL12,a third sub-pixel SPXL21, and a fourth sub-pixel SPXL22 arranged in asquare geometry of 2×2.

The first sub-pixel SPXL11 includes a photodiode PD11 formed by a firstphotoelectric converting region and a transfer transistor TG11-Tr.

The second sub-pixel SPXL12 includes a photodiode PD12 formed by asecond photoelectric converting region and a transfer transistorTG12-Tr.

The third sub-pixel SPXL21 includes a photodiode PD21 formed by a thirdphotoelectric converting region and a transfer transistor TG21-Tr.

The fourth sub-pixel SPXL22 includes a photodiode PD22 and a transfertransistor TG22-Tr.

In the multi-pixel MPXL20 in the pixel part 20, the four sub-pixelsSPXL11, SPXL12, SPXL21 and SPXL22 share a floating diffusion FD11, areset transistor RST11-Tr, a source follower transistor SF11-Tr, and aselection transistor SEL11-Tr.

In such a 4-sub-pixel sharing configuration, for example, the firstsub-pixel SPXL11 is configured as a G sub-pixel, the second sub-pixelSPXL12 is configured as an R sub-pixel, the third sub-pixel SPXL21 isconfigured as a B sub-pixel and the fourth sub-pixel SPXL22 isconfigured as an NIR sub-pixel. For example, the photodiode PD11 of thefirst sub-pixel SPXL11 operates as a first green (G) photoelectricconverting part, the photodiode PD12 of the second sub-pixel SPXL12operates as the red (R) photoelectric converting part, the photodiodePD21 of the third sub-pixel SPXL21 operates as a blue (B) photoelectricconverting part, and the photodiode PD22 of the fourth sub-pixel SPXL22operates as an near infrared (NIR) photoelectric converting part.

The photodiodes PD11, PD12, PD21, PD22 are, for example, pinnedphotodiodes (PPDs). On the substrate surface for forming the photodiodesPD11, PD12, PD21, PD22, there is a surface level due to dangling bondsor other defects, and therefore, a lot of charges (dark current) aregenerated due to heat energy, so that a correct signal fails to be readout. In a pinned photodiode (PPD), a charge accumulation part of thephotodiode PD can be buried in the substrate to reduce mixing of thedark current into signals.

The photodiodes PD11, PD12, PD21, PD22 generate signal charges (here,electrons) in an amount determined by the quantity of the incident lightand store the same. A description will be hereinafter given of a casewhere the signal charges are electrons and each transistor is an n-typetransistor. However, it is also possible that the signal charges areholes or each transistor is a p-type transistor.

The transfer transistor TG11-Tr is connected between the photodiode PD11and the floating diffusion FD11 and controlled through a control line(or a control signal) TG11. Under control of the reading part 70, thetransfer transistor TG11-Tr remains selected and in the conduction statein a period in which the control line TG11 is at a predetermined high(H) level, to transfer charges (electrons) produced by photoelectricconversion and stored in the photodiode PD11 to the floating diffusionFD11.

The transfer transistor TG12-Tr is connected between the photodiode PD12and the floating diffusion FD11 and controlled through a control line(or a control signal) TG12. Under control of the reading part 70, thetransfer transistor TG12-Tr remains selected and in the conduction statein a period in which the control line TG12 is at a predetermined high(H) level, to transfer charges (electrons) produced by photoelectricconversion and stored in the photodiode PD12 to the floating diffusionFD11.

The transfer transistor TG21-Tr is connected between the photodiode PD21and the floating diffusion FD11 and controlled through a control line(or a control signal) TG21. Under control of the reading part 70, thetransfer transistor TG21-Tr remains selected and in the conduction statein a period in which the control line TG21 is at a predetermined high(H) level, to transfer charges (electrons) produced by photoelectricconversion and stored in the photodiode PD21 to the floating diffusionFD11.

The transfer transistor TG22-Tr is connected between the photodiode PD22and the floating diffusion FD11 and controlled through a control line(or a control signal) TG22. Under control of the reading part 70, thetransfer transistor TG22-Tr remains selected and in the conduction statein a period in which the control line TG22 is at a predetermined high(H) level to transfer charges (electrons) produced by photoelectricconversion and stored in the photodiode PD22 to the floating diffusionFD11.

As shown in FIG. 6, the reset transistor RST11-Tr is connected between apower supply line VDD (or a power supply potential) and the floatingdiffusion FD11 and controlled through a control line (or a controlsignal) RST11. Alternatively, the reset transistor RST11-Tr may beconnected between a power supply line VRst different from the powersupply line VDD and the floating diffusion FD and controlled through thecontrol line (or the control signal) RST11. Under control of the readingpart 70, during a scanning operation for reading, for example, the resettransistor RST11-Tr remains selected and in the conduction state in aperiod in which the control line RST11 is at the H level, to reset thefloating diffusion FD11 to the potential of the power supply line VDD(or VRst).

The source follower transistor SF11-Tr and the selection transistorSEL11-Tr are connected in series between the power supply line VDD and avertical signal line LSGN. The floating diffusion FD11 is connected tothe gate of the source follower transistor SF11-Tr, and the selectiontransistor SEL11-Tr is controlled through a control line (or a controlsignal) SEL11. The selection transistor SEL11-Tr remains selected and inthe conduction state in a period in which the control line SEL11 is atthe H level. In this way, the source follower transistor SF11-Troutputs, to the vertical signal line LSGN, a read-out voltage (signal)of a column output VSL (PIXOUT), which is obtained by converting thecharges of the floating diffusion FD11 with a gain determined by thequantity of the charges (the potential) into a voltage signal.

The vertical scanning circuit 30 drives the sub-pixels in shutter andread-out rows through the row-scanning control lines under the controlof the timing control circuit 60. Furthermore, the vertical scanningcircuit 30 outputs, according to address signals, row selection signalsfor row addresses of the read-out rows from which signals are to be readout and the shutter rows in which the charges accumulated in thephotodiodes PD are reset.

In a normal pixel reading operation, the vertical scanning circuit 30 ofthe reading part 70 drives the pixels to perform shutter scanning andthen reading scanning.

The reading circuit 40 includes a plurality of column signal processingcircuits (not shown) arranged corresponding to the column outputs of thepixel part 20, and the reading circuit 40 may be configured such thatthe plurality of column signal processing circuits can perform columnparallel processing.

The reading circuit 40 may include a correlated double sampling (CDS)circuit, an analog-to-digital converter (ADC), an amplifier (AMP), asample/hold (S/H) circuit, and the like.

As mentioned above, as shown in FIG. 7A, for example, the readingcircuit 40 may include ADCs 41 for converting the read-out signals VSLfrom the column outputs of the pixel part 20 into digital signals.Alternatively, as shown in FIG. 7B, for example, the reading circuit 40may include amplifiers (AMPs) 42 for amplifying the read-out signals VSLfrom the column outputs of the pixel part 20. It is also possible that,as shown in FIG. 7C, for example, the reading circuit 40 may includesample/hold (S/H) circuits 43 for sampling/holding the read-out signalsVSL from the column outputs of the pixel part 20.

The horizontal scanning circuit 50 scans the signals processed in theplurality of column signal processing circuits of the reading circuit 40such as ADCs, transfers the signals in a horizontal direction, andoutputs the signals to a signal processing circuit (not shown).

The timing control circuit 60 generates timing signals required forsignal processing in the pixel part 20, the vertical scanning circuit30, the reading circuit 40, the horizontal scanning circuit 50, and thelike.

The above description has outlined the configurations and functions ofthe parts of the solid-state imaging device 10. Next, a description willbe given of the specific arrangement of the pixels according to thefirst embodiment.

FIGS. 8A to 8C schematically show an example configuration of thesolid-state imaging device (the CMOS image sensor) according to thefirst embodiment of the present invention. FIG. 8A is a plan viewschematically showing an example arrangement of the constituents of thesolid-state imaging device (the CMOS image sensor), which is formed asan NIR-RGB sensor. FIG. 8B is a simplified sectional view along the linex11-x12 in FIG. 8A. FIG. 8C is a simplified sectional view along theline y11-y12 in FIG. 8A.

In the present embodiment, a first direction refers to the columndirection (the horizontal or X direction), row direction (the verticalor Y direction) or diagonal direction of the pixel part 20 in which aplurality of pixels are arranged in a matrix pattern. The followingdescription is made with the first direction referring to the columndirection (the horizontal or X direction), for example. Accordingly, asecond direction refers to the row direction (the vertical or Ydirection).

In the pixel part 20 of FIG. 8A, the multi-pixel MPXL20 has foursub-pixels, namely, a first sub-pixel SPXL11, a second sub-pixel SPXL12,a third sub-pixel SPXL21, and a fourth sub-pixel SPXL22 arranged in asquare geometry of 2×2. More specifically, in the multi-pixel MPXL20,the first to fourth sub-pixels SPXL11, SPXL12, SPXL21 and SPXL22 arearranged in a square geometry such that the first sub-pixel SPXL11 isadjacent to the second sub-pixel SPXL12 in the first or X direction, thethird sub-pixel SPXL21 is adjacent to the fourth sub-pixel SPXL22 in thefirst or X direction, the first sub-pixel SPXL11 is adjacent to thethird sub-pixel SPXL21 in the second direction orthogonal to the firstdirection, or the Y direction and the second sub-pixel SPXL12 isadjacent to the fourth sub-pixel SPXL22 in the second or Y direction.

In the first embodiment, the first sub-pixel SPXL11 is configured as a Gsub-pixel SPXLG with a green (G) filter FLT-G that mainly transmitsgreen light, the second sub-pixel SPXL12 is configured as an R sub-pixelSPXLR with a red (R) filter FLT-R that mainly transmits red light, thethird sub-pixel SPXL21 is configured as a B sub-pixel SPXLB with a blue(B) filter FLT-B that mainly transmits blue light and the fourthsub-pixel SPXL22 is configured as a dedicated near-infrared (NIR)sub-pixel SPXLNI that receives infrared light.

The multi-pixel MPXL20 includes, as shown in FIGS. 8A, 8B and 8C, aphotoelectric converting part 210, a lens part 220, a color filter part230, an anti-reflective film 240, a first back side separating part 250,and a second back side separating part 260.

The light incident portion of the photoelectric converting part (PD10)210, which is a rectangular region RCT10 defined by four edges L11 toL14, is divided (segmented) into a first photoelectric converting region(PD11) 211, a second photoelectric converting region (PD12) 212, a thirdphotoelectric converting region (PD21) 213 and a fourth photoelectricconverting region (PD22) 214, which respectively correspond to the firstto fourth sub-pixels SPXL11, SPXL12, SPXL21, SPXL22. The photoelectricconverting part (PD10) 210 is divided (segmented), by the firstback-side separating part 250 and the second back-side separating part260, into four rectangular regions, namely, the first photoelectricconverting region (PD11) 211, the second photoelectric converting region(PD12) 212, the third photoelectric converting region (PD21) 213 and thefourth photoelectric converting region (PD22) 214. This will bedescribed in detail below.

The photoelectric converting part 210, which is divided (segmented) intothe first photoelectric converting region (PD11) 211, the secondphotoelectric converting region (PD12) 212, the third photoelectricconverting region (PD13) 213 and the fourth photoelectric convertingregion (PD14) 214, is buried in a semiconductor substrate 270 having afirst substrate surface 271 and a second substrate surface 272 oppositeto the first substrate surface 271, and is capable of photoelectricallyconverting received light and storing the resulting charges therein.

The color filter part 230 is provided on the first substrate surface 271side (the back surface side) of the first photoelectric convertingregion (PD11) 211, the second photoelectric converting region (PD12)212, the third photoelectric converting region (PD21) 213 and the fourthphotoelectric converting region (PD22) 214 of the photoelectricconverting part 210 with the anti-reflective film 240 being sandwichedtherebetween. The anti-reflective film 240 serves as a flattening layer.On the second substrate surface 272 side (the front surface side) of thefirst photoelectric converting region (PD11) 211, the secondphotoelectric converting region (PD12) 212, the third photoelectricconverting region (PD21) 213 and the fourth photoelectric convertingregion (PD22) 214, there are formed output parts OP11, OP12, OP21 andOP22 including, among others, an output transistor for outputting asignal determined by the charges produced by photoelectric conversionand stored.

The lens part 220 is formed by a single microlens MCL221 allowing lightto enter the first photoelectric converting region 211 of the firstsub-pixel SPXL11, the second photoelectric converting region 212 of thesecond sub-pixel SPXL12, the third photoelectric converting region 213of the third sub-pixel SPXL21 and the fourth photoelectric convertingregion 214 of the fourth sub-pixel SPXL22.

The optical center OCT1 of the single microlens MCL221 is positioned ina pixel center region RPCT where the boundaries of the four sub-pixels,namely, the first sub-pixel SPXL11, the second sub-pixel SPXL12, thethird sub-pixel SPXL21 and the fourth sub-pixel SPXL22 meet each other.

The color filter part 230 is segmented into a green (G) filter region231, a red (R) filter region 232, a blue (B) filter region 233, and anear infrared (NIR) filter region 234, to form the respective colorsub-pixels. The microlens MCL221 of the lens part 220 is provided on thelight entering side of the green (G) filter region 231, the red (R)filter region 232, the blue (B) filter region 233, and the near infrared(NIR) filter region 234.

As described above, the photoelectric converting part (PD10) 210, whichis the rectangular region RCT10 defined by the four edges L11 to L14, isdivided (segmented) by the first back side separating part 250 and thesecond back side separating part 260, into four rectangular regions,namely, the first photoelectric converting region (PD11) 211, the secondphotoelectric converting region (PD12) 212, the third photoelectricconverting region (PD21) 213 and the fourth photoelectric convertingregion (PD22) 214. More specifically, the light entering portion of thephotoelectric converting part (PD10) 210 is divided into four portionsby the back side separating part 250, which is basically positioned andshaped in the same manner as a back side metal (BSM).

The back-side separating part 250 includes a first separating part 251,a second separating part 252, a third separating part 253 and a fourthseparating part 254. The first separating part 251 has a length LG1 andextends between a center point PCT of the rectangular region RCT10defining the photoelectric converting part PD10 of the multi-pixelMPXL20 and a middle point CL11 of the edge L11. The second separatingpart 252 has a length LG2 and extends between the center point PCT and amiddle point CL12 of the edge L12. The third separating part 253 has alength LG3 and extends between the center point PCT and a middle pointCL13 of the edge L13. The fourth separating part 254 has a length LG4and extends between the center point PCT and a middle point CL14 of theedge L14. In other words, the first separating part 251 is formed at theboundary between the first photoelectric converting region 211 of thefirst sub-pixel SPXL11 and the second photoelectric converting region212 of the second sub-pixel SPXL12. The second separating part 252 isformed at the boundary between the third photoelectric converting region213 of the third sub-pixel SPXL21 and the fourth photoelectricconverting region 214 of the fourth sub-pixel SPXL22. The thirdseparating part 253 is formed at the boundary between the firstphotoelectric converting region 211 of the first sub-pixel SPXL11 andthe third photoelectric converting region 213 of the third sub-pixelSPXL21. The fourth separating part 254 is formed at the boundary betweenthe second photoelectric converting region 212 of the second sub-pixelSPXL12 and the fourth photoelectric converting region 214 of the fourthsub-pixel SPXL22.

In the first embodiment, like typical back side metal BSM, the back sideseparating part 250 is basically formed at the boundaries between thesub-pixels SPXL11, SPXL12, SPXL21 and SPXL22 such that the back sideseparating part 250 protrudes from the anti-reflective film 240 into thefilter part 230.

In the first embodiment, since the optical center OCT1 of the microlens221 is positioned in the pixel center region RPCT where the boundariesof the four sub-pixels, namely, the first, second, third and fourthsub-pixels SPXL11, SPXL12, SPXL21 and SPXL22 meet each other, a portionof the back side separating part 250 that is positioned in the opticalcenter region is made of such a material that this portion of the backside separating part 250 exhibits lower reflection (higher absorption)than the other portion of the back-side separating part outside theoptical center region.

In the back-side separating part 250, the first separating part 251includes a first low-reflection part 2511 that extends from the centerpoint PCT of the rectangular region RCT10 defining the photoelectricconverting part PD10, has a length l1 (l1<LG1), and is positioned withinthe optical center region, and the remaining part of the firstseparating part 251 (having a length of (LG1-l1) is formed as a backside metal part BSM1.

The second separating part 252 includes a second low-reflection part2521 that extends from the center point PCT of the rectangular regionRCT10, has a length l2 (l2<LG2), and is positioned within the opticalcenter region, and the remaining part of the second separating part 252(having a length of (LG2-l2) is formed as a back side metal part BSM2.

The third separating part 253 includes a third low-reflection part 2531that extends from the center point PCT of the rectangular region RCT10,has a length l3 (l3<LG3), and is positioned within the optical centerregion, and the remaining part of the third separating part 253 (havinga length of (LG3-l3) is formed as a back side metal part BSM3.

The fourth separating part 254 includes a fourth low-reflection part2541 that extends from the center point PCT of the rectangular regionRCT10, has a length l4 (l4<LG4), and is positioned within the opticalcenter region, and the remaining part of the fourth separating part 254(having a length of (LG4-l4) is formed as a back side metal part BSM4.

In the first embodiment, the length l1 of the first low-reflection part2511 of the first separating part 251, the length l2 of the secondlow-reflection part 2521 of the second separating part 252, the lengthl3 of the third low-reflection part 2531 of the third separating part253, and the length l4 of the fourth low-reflection part 2541 of thefourth separating part 254 are the same, for example (l1=l2=l3=l4).

The typical back side metal parts BSM1 to BSM4 are made of, for example,gold, aluminum, titanium, copper, chromium, palladium, nickel, silver,tungsten or the like. For example, the following materials can be usedas a material exhibiting lower reflection than the metal material of theback side metal parts BSM1 to BSM4.

For example, the following materials can be used as the material thatexhibits low reflection and high absorption in a specific wavelengthrange, for example, the NIR wavelengths (for example, 850 nm to 940 nm).

1) Inorganic dielectric material s such as oxides, silicon nitrides,hafnium, tantalum, tungsten, iridium (Ta₂O₅, WO₃, IrO_(x)) and WO₃, ITO(indium tin oxide), ATO (antimony tin oxide)) and any mixture of two ormore of these)

2) Black filter realized using organic absorptive functional dyes andconventional dyes, or ink (for example, (1) laminated naphthalimideanion radical (2) condensed porphyrin array, (3) doped polythiophene andother related conductive polymer, (4) sandwich-typelanthanide-bisphthalocyanine, (5) conjugated diquinone radical anion(also referred to as semi-quinone) and (6) mixed valence dinuclear metalcomplex)

3) one or more layers of multiple materials, a nano-structure (forexample, moth-eye) layer serving as an anti-reflective coating

The above-listed materials are example materials of the low-reflectionpart, and can be replaced with, for example, an implanted layer withp-type impurities or other low-reflection materials.

In the photoelectric converting part PD10, the second back sideseparating part 260 is formed as a trench-shaped back side separation,which is back side deep trench isolation (BDTI), such that the secondback side separating part 260 is aligned with the back side separatingpart 250 in the depth direction of the photoelectric converting part 210(the depth direction of the substrate 270: the Z direction).

A trench-shaped second separating part 261 is formed such that thesecond separating part 261 is aligned with the first separating part 251of the first back-side separating part 250 in the Z direction. Thetrench-shaped first separating part 261 includes a low-reflection part2611 that extends from the center point PCT of the rectangular regionRCT10 defining the photoelectric converting part PD10, has a length l1(l1<LG1) and is positioned within the optical center region, and theremaining part of the first separating part 261 (having a length of(LG1-l1) is formed as a trench-shaped back side deep isolation partBDTI1.

A trench-shaped second separating part 262 is formed such that thesecond separating part 262 is aligned with the second separating part252 of the first back side separating part 250 in the Z direction. Thetrench-shaped second separating part 262 includes a low-reflection part2621 that extends from the center point PCT of the rectangular regionRCT10, has a length l2 (l2<LG2) and is positioned within the opticalcenter region, and the remaining part of the second separating part 262(having a length of (LG2-l2) is formed as a trench-shaped back side deepisolation part BDTI2.

A trench-shaped third separating part 263 is formed such that the thirdseparating part 263 is aligned with the third separating part 253 of thefirst back side separating part 250 in the Z direction. Thetrench-shaped third separating part 263 includes a low-reflection part2631 that extends from the center point PCT of the rectangular regionRCT10, has a length l3 (l3<LG3) and is positioned within the opticalcenter region, and the remaining part of the third separating part 263(having a length of (LG3-l3) is formed as a trench-shaped back side deepisolation part BDTI3.

A trench-shaped fourth separating part 264 is formed such that thefourth separating part 264 is aligned with the fourth separating part254 of the first back-side separating part 250 in the Z direction. Thetrench-shaped fourth separating part 264 includes a low-reflection part2641 that extends from the center point PCT of the rectangular regionRCT10, has a length l4 (l4<LG4) and is positioned within the opticalcenter region, and the remaining part of the fourth separating part 264(having a length of (LG4-l4) is formed as a trench-shaped back side deepisolation part BDTI4.

In the low-reflection parts 2611, 2621, 2631 and 2641 of the second backside separating part 260, a layer made of a material exhibiting lowerreflection than the metal material of the back side metal parts BSM1 toBSM4 and the trench-shaped back side deep isolation parts BDTI1 to BDTI4is buried, like the low-reflection parts 2511, 2521, 2531 and 2541 ofthe first back-side separating part 250.

In the first embodiment, the multi-pixel MPXL20 includes the back sideseparating part 250 separating a plurality of adjacent sub-pixels fromeach other at least in the light entering portion of the photoelectricconverting region, the trench-shaped second back side separating part260, and the lens part 220 including a single microlens MCL221 allowinglight to enter the photoelectric converting regions PD11, PD12, PD21 andPD22 of the four sub-pixels SPXL11, SPXL12, SPXL21 and SPXL22. In thefirst embodiment, the optical center of the microlens MCL221 of the lenspart 220 is positioned at the location where the first back sideseparating part 250 and the second back side separating part 260 areformed, and the first back side separating part 250 and the second backside separating part 260 are each formed such that at least the opticalcenter region of the back side separating part exhibits lower reflection(higher absorption) than the other region of the back side separatingpart.

With the above-described configurations, every sub-pixel can havedistance information in the first embodiment, which can be applied toprovide for the PDAF capability. Even if the optical center of themicrolens is positioned at the location where the back side metal (BSM)is formed, the radical reduction in the sensitivity at the opticalcenter, which may be caused by reflection, can be prevented. As aconsequence, the first embodiment produces little crosstalk betweenadjacent sub-pixels, can reduce the influence of the luminance shading,and even prevent the degradation in the sensitivity at the opticalcenter.

Second Embodiment

FIGS. 9A to 9C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a secondembodiment of the present invention. FIG. 9A is a plan viewschematically showing an example arrangement of constituents of thesolid-state imaging device (the CMOS image sensor) formed as an NIR-RGBsensor. FIG. 9B is a simplified sectional view along the line x11-x12 inFIG. 9A. FIG. 9C is a simplified sectional view along the line y11-yl2in FIG. 9A.

The second embodiment differs from the first embodiment in the followingpoints. In the first embodiment, since the optical center OCT1 of themicrolens MCL221 is positioned in the pixel center region RPCT where theboundaries of the four sub-pixels, namely, the first, second, third andfourth sub-pixels SPXL11, SPXL12, SPXL21 and SPXL22 meet each other, alow-reflection part is defined in the first to fourth separating parts251 to 254 of the back side separating part 250. The low reflectionparts of the first to fourth separating parts 251 to 254 are located inthe optical center region ROCT1 and made of such a material that thelow-reflection parts exhibit lower reflection (higher absorption) thanthe other region of the back side separating part outside the opticalcenter region OCT1.

In the second embodiment, on the other hand, the first to fourthseparating parts 251A to 254A of the first back side separating part 250are entirely configured as a low-reflection part or made of alow-reflection (high-absorption) material, not only in the partcorresponding to the optical center region. Likewise, the first tofourth separating parts 261A to 264A of the second back side separatingpart 260 are entirely configured as a low-reflection part or made of alow-reflection (high-absorption) material.

The second embodiment not only produces the same effects as theabove-described first embodiment but also can further prevent radicalreduction in the sensitivity at the optical center, which may be causedby reflection or the like, even if the optical center of the microlensis positioned at the location where the back-side metal (BSM) is formed.

Third Embodiment

FIGS. 10A to 10C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a thirdembodiment of the present invention. FIG. 10A is a plan viewschematically showing an example arrangement of constituents of thesolid-state imaging device (the CMOS image sensor) formed as an NIR-RGBsensor. FIG. 10B is a simplified sectional view along the line x11-x12in FIG. 10A. FIG. 10C is a simplified sectional view along the liney11-y12 in FIG. 10A.

The third embodiment differs from the first embodiment in the followingpoints. In the first embodiment, since the optical center OCT1 of themicrolens 221 is positioned in the pixel center region RPCT where theboundaries of the four sub-pixels, namely, the first, second, third andfourth sub-pixels SPXL11, SPXL12, SPXL21 and SPXL22 meet each other, alow-reflection part is defined in the first to fourth separating parts251 to 254 of the back-side separating part 250. The low reflectionparts of the first to fourth separating parts 251 to 254 are located inthe optical center region ROCT1 and made of such a material that thelow-reflection parts exhibit lower reflection (higher absorption) thanthe other region of the back side separating part outside the opticalcenter region OCT1.

In the third embodiment, on the other hand, the back side metal partsBSM1 to BSM4 are removed in the low-reflection parts 2511B, 2521B, 2531Band 2541B of the first to fourth separating parts 251B to 254B of thefirst back side separating part 250B, so that low reflection (highabsorption) is achieved in the low-reflection parts. The trench-shapedback-side deep isolation parts BDTI1 to BDTI4 of the low reflectionparts 2611B, 2621B, 2631B and 2641B of the first to fourth separatingparts 261B to 264B of the second back side separating part 260B are madeof a low-reflection (high-absorption) material.

The third embodiment not only produce the same effects as theabove-described first embodiment but also can further prevent radicalreduction in the sensitivity at the optical center, which may be causedby reflection or the like, even if the optical center of the microlensis positioned at the location where the back-side metal (BSM) is formed.

Fourth Embodiment

FIGS. 11A to 11C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a fourthembodiment of the present invention. FIG. 11A is a plan viewschematically showing an example arrangement of constituents of thesolid-state imaging device (the CMOS image sensor) formed as a sensorhaving partial PDAF capability in the multi-pixel. FIG. 11B is asimplified sectional view along the line x11-x12 in FIG. 11A. FIG. 11Cis a simplified sectional view along the line y11-y12 in FIG. 11A.

The fourth embodiment differs from the first embodiment in the followingpoints. In the first embodiment, the lens part 220 of the multi-pixelMPXL20C includes a single microlens MCL221C allowing light to enter thephotoelectric converting regions PD11, PD12, PD21 and PD22 of the foursub-pixels SPXL11, SPXL12, SPXL21 and SPXL22, the optical center of themicrolens is positioned at the location where the first and second backside separating parts 250C and 260C are formed, and the first and secondback-side separating parts 250C and 260C are formed such that at leastthe optical center region of the back side separating parts exhibitslower reflection (higher absorption) than the other region of the backside separating parts.

In the fourth embodiment, on the other hand, the lens part 220 of themulti-pixel MPXL20C includes a first microlens MCL221C allowing light toenter the first photoelectric converting region PD11 of the firstsub-pixel SPXL11 and the second photoelectric converting region PD12 ofthe second sub-pixel SPXL12, a second microlens MCL222C allowing lightto enter the third photoelectric converting region PD21 of the thirdsub-pixel SPXL21, and a third microlens MCL223C allowing light to enterthe fourth photoelectric converting region PD22 of the fourth sub-pixelSPXL22. The optical center of the first microlens MCL221C is positionedin a center region CT12 of a boundary region RBD12 between the firstphotoelectric converting region PD11 of the first sub-pixel SPXL11 andthe second photoelectric converting region PD12 of the second sub-pixelSPXL12. A low-reflection part is defined in the first separating part251C of the first back side separating part 250C (and the firstseparating part 261C of the second back side separating part 260C),which is positioned in the boundary region RBD12. The low-reflectionpart is positioned in the center region CT12 of the boundary regionRBD12, which includes the optical center, and made of a material thatexhibits lower reflection (higher absorption) than the other region ofthe back side separating part outside the optical center region.

In the solid-state imaging device 10C relating to the fourth embodiment,in the boundary region the first photoelectric converting region (PD11)211 of the first sub-pixel SPXL11 and the second photoelectricconverting region (PD12) 212 of the second sub-pixel SPXL12, the firstseparating parts 251C and 261C are formed that include therein alow-reflection part positioned in the center region CT12 of the boundaryregion. Second separating parts 252C and 262C without a low-reflectionpart are formed in the boundary region between the third photoelectricconverting region (PD21) 213 of the third sub-pixel SPXL21 and thefourth photoelectric converting region (PD22) 214 of the fourthsub-pixel SPXL22. Third separating parts 253C and 263C without alow-reflection part are formed in the boundary region between the firstphotoelectric converting region (PD11) 211 of the first sub-pixel SPXL11and the third photoelectric converting region (PD21) 213 of the thirdsub-pixel SPXL21. Fourth separating parts 254C and 264C without alow-reflection part are formed in the boundary region between the secondphotoelectric converting region (PD12) 212 of the second sub-pixelSPXL12 and the fourth photoelectric converting region (PD22) 214 of thefourth sub-pixel SPXL22.

Here, the optical center of the second microlens MCL222C coincides withthe optical center of the third photoelectric converting region PD21,and the optical center of the third microlens MCL223C coincides with theoptical center of the fourth photoelectric converting region PD22.

In the solid-state imaging device 10C relating to the fourth embodiment,the two sub-pixels sharing the microlens MCL11, namely, the first andsecond sub-pixels SPXL11 and SPXL12, are partially capable of havingPDAF information. In the example shown in FIGS. 11A to 11C, the firstsub-pixel SPXL11 can have information PDAF1, and the second sub-pixelSPXL12 can have information PDAF2. On the other hand, the third andfourth sub-pixels SPXL21 and SPXL22, which share no microlens, do nothave information PDAF.

Modification Examples of Fourth Embodiment

FIGS. 12A to 12C schematically show a modification example of thesolid-state imaging device (the CMOS image sensor) according to thefourth embodiment of the present invention.

FIG. 12A is a plan view showing a first modification example of thesolid-state imaging device (the CMOS image sensor) formed as a sensorthat partially provides for PDAF capability in the multi-pixel.

The first modification example of FIG. 12A includes a first microlensMCL221D allowing light to enter the first photoelectric convertingregion PD11 of the first sub-pixel SPXL11 and the third photoelectricconverting region PD21 of the third sub-pixel SPXL21, a second microlensMCL222D allowing light to enter the second photoelectric convertingregion PD12 of the second sub-pixel SPXL12, and a third microlensMCL223D allowing light to enter the fourth photoelectric convertingregion PD22 of the fourth sub-pixel SPXL22. The optical center of thefirst microlens MCL221D is positioned in a center region CT13 of aboundary region RBD13 between the first photoelectric converting regionPD11 of the first sub-pixel SPXL11 and the third photoelectricconverting region PD21 of the third sub-pixel SPXL21. A low-reflectionpart is defined in the third separating part 253D of the first back sideseparating part 250D (and the third separating part 263D of the secondback side separating part 260D), which is positioned in the boundaryregion RBD13. The low-reflection part is positioned in a center regionCT13 of the boundary region RBD13, which includes the optical center,and made of a material that exhibits lower reflection (higherabsorption) than the other region of the back side separating partoutside the optical center region.

In the first modification example, first separating parts 251D and 261Dwithout a low-reflection part are formed in the boundary region betweenthe first photoelectric converting region PD11 of the first sub-pixelSPXL11 and the second photoelectric converting region PD12 of the secondsub-pixel SPXL12. Second separating parts 252D and 262D without alow-reflection part are formed in the boundary region between the thirdphotoelectric converting region PD 21 of the third sub-pixel SPXL21 andthe fourth photoelectric converting region PD22 of the fourth sub-pixelSPXL22. In the boundary region between the first photoelectricconverting region PD11 of the first sub-pixel SPXL11 and the thirdphotoelectric converting region PD21 of the third sub-pixel SPXL21, thethird separating parts 253D and 263D with a low-reflection part beingpositioned in the center region CT13 of the boundary region are formed.Fourth separating parts 254D and 264D without a low-reflection part areformed in the boundary region between the second photoelectricconverting region PD12 of the second sub-pixel SPXL12 and the fourthphotoelectric converting region PD22 of the fourth sub-pixel SPXL22.

Here, the optical center of the second microlens MCL222D coincides withthe optical center of the second photoelectric converting region PD12,and the optical center of the third microlens MCL223D coincides with theoptical center of the fourth photoelectric converting region PD22.

In the first modification example, the two sub-pixels sharing themicrolens MCL221D, namely, the first and third sub-pixels SPXL11 andSPXL21, which, are partially capable of having PDAF information. In theexample shown in FIG. 12A, the first sub-pixel SPXL11 can haveinformation PDAF1, and the third sub-pixel SPXL21 can have informationPDAF2. On the other hand, the second and fourth sub-pixels SPXL12 andSPXL22, which share no microlens, do not have information PDAF.

FIG. 12B is a plan view showing a second modification example of thesolid-state imaging device (the CMOS image sensor) formed as a sensorthat partially provides for PDAF capability in the multi-pixel.

The second modification example of FIG. 12B includes a first microlensMCL221E allowing light to enter the third photoelectric convertingregion PD21 of the third sub-pixel SPXL21 and the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22, a secondmicrolens MCL222E allowing light to enter the first photoelectricconverting region PD11 of the first sub-pixel SPXL11, and a thirdmicrolens MCL223E allowing light to enter the second photoelectricconverting region PD12 of the second sub-pixel SPXL12. The opticalcenter of the first microlens MCL221E is positioned in a center regionCT34 of a boundary region RBD34 between the third photoelectricconverting region PD21 of the third sub-pixel SPXL21 and the fourthphotoelectric converting region PD22 of the fourth sub-pixel SPXL22. Alow-reflection part is defined in the second separating part 252E of thefirst back side separating part 250E (and the second separating part262E of the second back side separating part 260E), which is positionedin the boundary region RBD34. The low-reflection part is positioned inthe center region CT34 of the boundary region RBD34, which includes theoptical center, and made of a material that exhibits lower reflection(higher absorption) than the other region of the back side separatingpart outside the optical center region.

In the second modification example, first separating parts 251E and 261Ewithout a low-reflection part are formed in the boundary region betweenthe first photoelectric converting region PD11 of the first sub-pixelSPXL11 and the second photoelectric converting region PD12 of the secondsub-pixel SPXL12. In the boundary region between the third photoelectricconverting region PD21 of the third sub-pixel SPXL21 and the fourthphotoelectric converting region PD22 of the fourth sub-pixel SPXL22,second separating parts 252E and 262E with a low-reflection part beingpositioned in a center region CT34 of the boundary region are formed.Third separating parts 253E and 263E without a low-reflection part areformed in the boundary region between the first photoelectric convertingregion 211 of the first sub-pixel SPXL11 and the third photoelectricconverting region PD21 of the third sub-pixel SPXL22. Fourth separatingparts 254E and 264E without a low-reflection part are formed in theboundary region between the second photoelectric converting region PD12of the second sub-pixel SPXL12 and the fourth photoelectric convertingregion PD22 of the fourth sub-pixel SPXL22.

Here, the optical center of the second microlens MCL222E coincides withthe optical center of the first photoelectric converting region PD11,and the optical center of the third microlens MCL223E coincides with theoptical center of the second photoelectric converting region PD12.

In the second modification example, the sub-pixels sharing the microlensMCL11, namely, the third and fourth sub-pixels SPXL21 and SPXL22 arepartially capable of having PDAF information. In the example shown inFIG. 12B, the third sub-pixel SPXL21 can have information PDAF1, and thefourth sub-pixel SPXL22 can have information PDAF2. On the other hand,the first and second sub-pixels SPXL11 and SPXL12, which share nomicrolens, do not have information PDAF.

FIG. 12C is a plan view showing a third modification example of thesolid-state imaging device (the CMOS image sensor) formed as a sensorthat partially provides for PDAF capability in the multi-pixel.

The third modification example of FIG. 12C includes a first microlensMCL221F allowing light to enter the second photoelectric convertingregion PD12 of the second sub-pixel SPXL12 and the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22, a secondmicrolens MCL222F allowing light to enter the first photoelectricconverting region PD11 of the first sub-pixel SPXL11, and a thirdmicrolens MCL223F allowing light to enter the second photoelectricconverting region PD21 of the third sub-pixel SPXL21. The optical centerof the first microlens MCL221F is positioned in a center region CT24 ofa boundary region RBD24 between the second photoelectric convertingregion PD12 of the second sub-pixel SPXL12 and the fourth photoelectricconverting region PD222 of the fourth sub-pixel SPXL22. A low-reflectionpart is defined in the fourth separating part 254F of the first backside separating part 250F (and the first separating part 264F of thesecond back side separating part 260F), which is positioned in theboundary region RBD24. The low-reflection part is positioned in thecenter region CT24 of the boundary region RBD24, which includes theoptical center, and made of a material that exhibits lower reflection(higher absorption) than the other region of the back side separatingpart outside the optical center region.

In the third modification example, first separating parts 251F and 261Fwithout a low-reflection part are formed in the boundary region betweenthe first photoelectric converting region PD11 of the first sub-pixelSPXL11 and the second photoelectric converting region PD12 of the secondsub-pixel SPXL12. Second separating parts 252F and 262F without alow-reflection part are formed in the boundary region between the thirdphotoelectric converting region PD21 of the third sub-pixel SPXL21 andthe fourth photoelectric converting region PD22 of the fourth sub-pixelSPXL22. Third separating parts 253F and 263F without a low-reflectionpart are formed in the boundary region between the first photoelectricconverting region PD11 of the first sub-pixel SPXL11 and the thirdphotoelectric converting region PD21 of the third sub-pixel SPXL21. Inthe boundary region between the second photoelectric converting regionPD12 of the second sub-pixel SPXL12 and the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22, the fourthseparating parts 254F and 264F with a low-reflection part beingpositioned in the center region CT24 of the boundary region are formed.

Here, the optical center of the second microlens MCL222F coincides withthe optical center of the first photoelectric converting region PD11,and the optical center of the third microlens MCL223F coincides with theoptical center of the third photoelectric converting region PD21.

In the third modification example, the two sub-pixels sharing themicrolens MCL221F, namely, the second and fourth sub-pixels SPXL12 andSPXL22 are partially capable of having PDAF information. In the exampleshown in FIG. 12C, the second sub-pixel SPXL12 can have informationPDAF1, and the fourth sub-pixel SPXL22 can have information PDAF2. Onthe other hand, the first and third sub-pixels SPXL11 and SPXL21, whichshare no microlens, do not have information PDAF.

The fourth embodiment can produce the same effects as theabove-described first embodiment, more specifically, produces littlecrosstalk between adjacent sub-pixels, can reduce the influence of theluminance shading, and can even prevent the degradation in thesensitivity at the optical center. Furthermore, the sub-pixels sharing asingle microlens can provide for PDAF capability.

Fifth Embodiment

FIGS. 13A to 13C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a fifthembodiment of the present invention. FIG. 13A is a plan viewschematically showing an example arrangement of constituents of thesolid-state imaging device (the CMOS image sensor) formed as a sensorthat partially provides for PDAF capability in the multi-pixel. FIG. 13Bis a simplified sectional view along the line x11-x12 in FIG. 13A. FIG.13C is a simplified sectional view along the line y11-y12 in FIG. 13A.

The fifth embodiment differs from the fourth embodiment in the followingpoints. In the fourth embodiment, the optical center of the firstmicrolens MCL221C is positioned in the center region CT12 of theboundary region RBD12 between the first photoelectric converting regionPD11 of the first sub-pixel SPXL11 and the second photoelectricconverting region PD12 of the second sub-pixel SPXL12. A low-reflectionpart is defined in the first separating part 251C of the first back sideseparating part 250C (and the first separating part 261C of the secondback side separating part 260C), which is positioned in the boundaryregion RBD12. The low-reflection part is positioned in the center regionCT12 of the boundary region RBD12, which includes the optical center,and made of a material that exhibits lower reflection (higherabsorption) than the other region of the back side separating partoutside the optical center region.

In the fifth embodiment, on the other hand, the first separating part251G of the first back-side separating part 250G is entirely configuredas a low-reflection part or made of a low-reflection (high-absorption)material, not only in the part corresponding to the optical centerregion. Likewise, the first separating part 261G of the second back sideseparating part 260G is entirely configured as a low-reflection part ormade of a low-reflection (high-absorption) material.

The above configurations can be applied to the above-described first,second and third modification examples.

The fifth embodiment not only produces the same effects as theabove-described fourth embodiment but also can further prevent theradical reduction in the sensitivity at the optical center, which may becaused by reflection or the like, even if the optical center of themicrolens is positioned at the location where the back-side metal (BSM)is formed.

Sixth Embodiment

FIGS. 14A to 14C schematically show an example configuration of asolid-state imaging device (a CMOS image sensor) according to a sixthembodiment of the present invention. FIG. 14A is a plan viewschematically showing an example arrangement of constituents of thesolid-state imaging device (the CMOS image sensor) formed as a sensorthat partially provides for PDAF capability in the multi-pixel. FIG. 14Bis a simplified sectional view along the line x11-x12 in FIG. 14A. FIG.14C is a simplified sectional view along the line y11-y12 in FIG. 14A.

The sixth embodiment differs from the fourth and fifth embodiments inthe following points. In the fourth and fifth embodiments, alow-reflection part is defined in the first separating parts 251C and251G of the first back side separating parts 250C and 250G, which arearranged in the boundary region RBD12 between the first photoelectricconverting region PD11 of the first sub-pixel SPXL11 and the secondphotoelectric converting region PD12 of the second sub-pixel SPXL12. Thelow-reflection part is positioned in the center region CT12 of theboundary region RBD12, which includes the optical center, and made of amaterial that exhibits lower reflection (higher absorption) than theother region of the back side separating part outside the optical centerregion. Alternatively, the first separating parts 251C and 251G of thefirst back side separating parts 250C and 250G are entirely configuredas a low-reflection part or made of a low-reflection (high-absorption)material, not only in the part corresponding to the optical centerregion.

In the sixth embodiment, on the other hand, the back side metal partBSM1 is removed in the low-reflection part of the first separating part251H of the first back side separating part 250H, so that low reflection(high absorption) is achieved in the low-reflection part.

The above configurations can be applied to the above-described first,second and third modification examples.

The sixth embodiment not only produces the same effects as theabove-described fourth and fifth embodiments but also can furtherprevent the radical reduction in the sensitivity at the optical center,which may be caused by reflection or the like, even if the opticalcenter of the microlens is positioned at the location where the backside metal (BSM) is formed.

Seventh Embodiment

FIG. 15 schematically shows an example configuration of a solid-stateimaging device (a CMOS image sensor) according to a seventh embodimentof the present invention.

The seventh embodiment differs from the fourth embodiment in thefollowing points. The fourth embodiment includes the first microlensMCL221C allowing light to enter the first photoelectric convertingregion PD11 of the first sub-pixel SPXL11 and the second photoelectricconverting region PD12 of the second sub-pixel SPXL12, the secondmicrolens MCL222C allowing light to enter the third photoelectricconverting region PD21 of the third sub-pixel SPXL21, and the thirdmicrolens MCL223C allowing light to enter the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22. A low-reflectionpart is defined in the first separating part 251C of the first back sideseparating part 250C (and the first separating part 261C of the secondback side separating part 260C), which is arranged in the boundaryregion RBD12 between the first photoelectric converting region PD11 ofthe first sub-pixel SPXL11 and the second photoelectric convertingregion PD12 of the second sub-pixel SPXL12. The low-reflection part ispositioned in the center region CT12 of the boundary region RBD12, whichincludes the optical center, and made of a material that exhibits lowerreflection (higher absorption) than the other region of the back sideseparating part outside the optical center region.

In the solid-state imaging device 10I relating to the seventhembodiment, on the other hand, the third and fourth sub-pixels SPXL21and SPXL22 share the microlens MCL222I, so that the two sub-pixelssharing the microlens MCL222I, namely, the third and fourth sub-pixelsSPXL21 and SPXL22 are also partially capable of having PDAF information.

In the boundary region between the first photoelectric converting regionPD11 of the first sub-pixel SPXL11 and the second photoelectricconverting region PD12 of the second sub-pixel SPXL12, first separatingparts 251I and 261I are formed and have a low-reflection part definedtherein and positioned in a center region CT12 of the boundary region.In the boundary region between the third photoelectric converting regionPD21 of the third sub-pixel SPXL21 and the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22, second separatingparts 252I and 262I are formed and have a low-reflection part definedtherein and positioned in a center region CT34 of the boundary region.Third separating parts 253I and 263I without a low-reflection part areformed in the boundary region between the first photoelectric convertingregion PD11 of the first sub-pixel SPXL11 and the third photoelectricconverting region PD21 of the third sub-pixel SPXL21. Fourth separatingparts 254I and 264I without a low-reflection part are formed in theboundary region between the second photoelectric converting region PD12of the second sub-pixel SPXL12 and the fourth photoelectric convertingregion PD22 of the fourth sub-pixel SPXL22.

The solid-state imaging device 10I shown in FIG. 15 can be configured asan M-NIR sensor, like the solid-state imaging device of FIGS. 4A to 4C.

In the solid-state imaging device 10I relating to the seventhembodiment, the first and second sub-pixels SPXL11 and SPXL12 sharingthe microlens MCL221I are partially capable of having PDAF information,and so are the third and fourth sub-pixels SPXL21 and SPXL22 sharing themicrolens MCL222I. In the example shown in FIG. 15, the first sub-pixelSPXL11 can have information PDAF1, the second sub-pixel SPXL12 can haveinformation PDAF2, the third sub-pixel SPXL21 can have informationPDAF3, and the fourth sub-pixel SPXL22 can have information PDAF4.

Modification Example of Seventh Embodiment

FIG. 16 schematically shows a modification example of the solid-stateimaging device (the CMOS image sensor) according to the seventhembodiment of the present invention.

The modification example of FIG. 16 includes a first microlens MCL221Jallowing light to enter the first photoelectric converting region PD11of the first sub-pixel SPXL11 and the third photoelectric convertingregion PD21 of the third sub-pixel SPXL21, and a second microlensMCL222J allowing light to enter the second photoelectric convertingregion PD12 of the second sub-pixel SPXL12 and the fourth photoelectricconverting region PD22 of the fourth sub-pixel SPXL22.

The optical center of the first microlens MCL221J is positioned in acenter region CT13 of a boundary region RBD13 between the firstphotoelectric converting region PD11 of the first sub-pixel SPXL11 andthe third photoelectric converting region PD21 of the third sub-pixelSPXL21. A low-reflection part is defined in the first separating part253J of the first back side separating part 250J (and the firstseparating part 263C of the second back side separating part 260J),which is positioned in the boundary region RBD13. The low-reflectionpart is positioned in the center region CT13 of the boundary regionRBD13, which includes the optical center, and made of a material thatexhibits lower reflection (higher absorption) than the other region ofthe back side separating part outside the optical center region.

The optical center of the second microlens MCL12 is positioned in acenter region CT24 of a boundary region RBD24 between the secondphotoelectric converting region PD12 of the second sub-pixel SPXL12 andthe fourth photoelectric converting region PD22 of the fourth sub-pixelSPXL22. A low-reflection part is defined in the first separating part254J of the first back side separating part 250J (and the firstseparating part 264J of the second back side separating part 260J),which is positioned in the boundary region RBD24. The low-reflectionpart is positioned in the center region CT24 of the boundary regionRBD24, which includes the optical center, and made of a material thatexhibits lower reflection (higher absorption) than the other region ofthe back side separating part outside the optical center region.

In the present modification example, first separating parts 251J and261J without a low-reflection part are formed in the boundary regionbetween the first photoelectric converting region PD11 of the firstsub-pixel SPXL11 and the second photoelectric converting region PD12 ofthe second sub-pixel SPXL12. Second separating parts 252J and 262Jwithout a low-reflection part are formed in the boundary region betweenthe third photoelectric converting region PD21 of the third sub-pixelSPXL21 and the fourth photoelectric converting region PD22 of the fourthsub-pixel SPXL22. In the boundary region between the first photoelectricconverting region PD11 of the first sub-pixel SPXL11 and the thirdphotoelectric converting region PD21 of the third sub-pixel SPXL21,third separating parts 253J and 263J having a low-reflection partdefined therein and positioned in the center region CT13 of the boundaryregion are formed. In the boundary region between the secondphotoelectric converting region PD12 of the second sub-pixel SPXL12 andthe fourth photoelectric converting region PD22 of the fourth sub-pixelSPXL22, fourth separating parts 254J and 264J having a low-reflectionpart defined therein and positioned in the center region CT24 of theboundary region are formed.

In the present modification example, the first and third sub-pixelsSPXL11 and SPXL21 sharing the microlens MCL221J are partially capable ofhaving PDAF information, and so are the second and fourth sub-pixelsSPXL12 and SPXL22 sharing the microlens MCL222J. In the example shown inFIG. 16, the first sub-pixel SPXL11 can have information PDAF1, thethird sub-pixel SPXL21 can have information PDAF2, the second sub-pixelSPXL12 can have information PDAF3, and the fourth sub-pixel SPXL22 canhave information PDAF4.

The seventh embodiment can produce the same effects as theabove-described first and fourth embodiments, more specifically,produces little crosstalk between adjacent sub-pixels, can reduce theinfluence of the luminance shading, and can even prevent the degradationin the sensitivity at the optical center. Furthermore, the sub-pixelssharing a single microlens can provide for PDAF capability.

In the present embodiment, in the vicinity of the optical center of themulti-pixel in which at least one microlens is shared by sub-pixels, theback side separating part, the back side separating part and thetrench-shaped back side separating part, or, if the back side separatingpart is removed, the trench-shaped back side separating part can bealternatively made of a low-reflection material.

The solid-state imaging devices 10, and 10A to 10J described above canbe applied, as an imaging device, to electronic apparatuses such asdigital cameras, video cameras, mobile terminals, surveillance cameras,and medical endoscope cameras.

FIG. 17 shows an example configuration of an electronic apparatusincluding a camera system to which the solid-state imaging devicesaccording to the embodiments of the present invention can be applied.

As shown in FIG. 17, the electronic apparatus 100 includes a CMOS imagesensor 110 that can be constituted by the solid-state imaging devices10, 10A to 10J relating to the embodiments of the present invention. Theelectronic apparatus 100 further includes an optical system (such as alens) 120 for redirecting the incident light to the pixel region of theCMOS image sensor 110 (to form a subject image). The electronicapparatus 100 includes a signal processing circuit (PRC) 130 forprocessing the output signals from the CMOS image sensor 110.

The signal processing circuit 130 performs predetermined signalprocessing on the output signals from the CMOS image sensor 110. Theimage signals resulting from the processing in the signal processingcircuit 130 can be handled in various manners. For example, the imagesignals can be displayed as a video image on a monitor having a liquidcrystal display, printed by a printer, or recorded directly on a storagemedium such as a memory card.

As described above, if the above-described solid-state imaging devices10, 10A to 10G are mounted as the CMOS image sensor 110, the camerasystem can achieve high-performance, compactness, and low-cost.Accordingly, the embodiments of the present invention can provide forelectronic apparatuses such as surveillance cameras and medicalendoscope cameras, which are used for applications where the cameras areinstalled under restricted conditions from various perspectives such asthe installation size, the number of connectable cables, the length ofcables and the installation height.

What is claimed is:
 1. A solid-state imaging device comprising amulti-pixel including at least two sub-pixels, each sub-pixel having aphotoelectric converting region, wherein the multi-pixel includes: aback side separating part separating a plurality of adjacent sub-pixelsfrom each other at least in a light entering portion of thephotoelectric converting region thereof; and a single lens part allowinglight to enter the photoelectric converting region of at least two ofthe sub-pixels, wherein the lens part is arranged such that an opticalcenter thereof is positioned at a location where the back sideseparating part is formed, and wherein the back side separating part isformed such that at least an optical center region thereof exhibitslower reflection than the other region of the back side separating part.2. The solid-state imaging device according to claim 1, wherein the backside separating part is formed such that the optical center regionthereof exhibits lower reflection than the other region of the back sideseparating part.
 3. The solid-state imaging device according to claim 1,wherein the back-side separating part is formed such that the opticalcenter region and the other region of the back-side separating partexhibit low reflection.
 4. The solid-state imaging device according toclaim 1, wherein a low reflection part of the back side separating partexhibiting lower reflection is made of a material exhibiting lowreflection within a specific wavelength range.
 5. The solid-stateimaging device according to claim 1, wherein, from the back-sideseparating part, a material forming the back side separating part isremoved so that the lower reflection is achieved.
 6. The solid-stateimaging device according to claim 1, wherein the multi-pixel furtherincludes a trench-shaped back side separating part formed in thephotoelectric converting region, the trench-shaped back side separatingpart aligned with the back-side separating part in a depth direction ofthe photoelectric converting region.
 7. The solid-state imaging deviceaccording to claim 6, wherein the trench-shaped back-side separatingpart exhibits low reflection.
 8. The solid-state imaging deviceaccording to claim 6, wherein, in a vicinity of an optical center of themulti-pixel in which at least one lens part is shared by sub-pixels, theback side separating part, the back side separating part and thetrench-shaped back side separating part, or, if the back side separatingpart is removed, the trench-shaped back side separating part can bealternatively made of a low-reflection material.
 9. The solid-stateimaging device according to claim 1, wherein, in the multi-pixel, afirst sub-pixel, a second sub-pixel, a third sub-pixel and a fourthsub-pixel are arranged in a square geometry such that, in a firstdirection, the first sub-pixel is adjacent to the second sub-pixel andthe third sub-pixel is adjacent to the fourth sub-pixel and that, in asecond direction orthogonal to the first direction, the first sub-pixelis adjacent to the third sub-pixel and the second sub-pixel is adjacentto the fourth sub-pixel, wherein the lens part is formed by a singlemicrolens allowing light to enter a first photoelectric convertingregion of the first sub-pixel, a second photoelectric converting regionof the second sub-pixel, a third photoelectric converting region of thethird sub-pixel and a fourth photoelectric converting region of thefourth sub-pixel, and wherein an optical center of the single microlensis positioned in a pixel center region where a boundary of the firstsub-pixel, a boundary of the second sub-pixel, a boundary of the thirdsub-pixel and a boundary of the fourth sub-pixel meet each other. 10.The solid-state imaging device according to claim 1, wherein, in themulti-pixel, a first sub-pixel, a second sub-pixel, a third sub-pixeland a fourth sub-pixel are arranged in a square geometry such that, in afirst direction, the first sub-pixel is adjacent to the second sub-pixeland the third sub-pixel is adjacent to the fourth sub-pixel and that, ina second direction orthogonal to the first direction, the firstsub-pixel is adjacent to the third sub-pixel and the second sub-pixel isadjacent to the fourth sub-pixel, and wherein the lens part includes: afirst microlens allowing light to enter a first photoelectric convertingregion of the first sub-pixel and a second photoelectric convertingregion of the second sub-pixel; a second microlens allowing light toenter a third photoelectric converting region of the third sub-pixel;and a third microlens allowing light to enter a fourth photoelectricconverting region of the fourth sub-pixel, and the lens part isstructured such that an optical center of the first microlens ispositioned at least in a center region of a boundary region between thefirst photoelectric converting region of the first sub-pixel and thesecond photoelectric converting region of the second sub-pixel, orwherein the lens part includes: a first microlens allowing light toenter a first photoelectric converting region of the first sub-pixel anda third photoelectric converting region of the third sub-pixel; a secondmicrolens allowing light to enter a second photoelectric convertingregion of the second sub-pixel; and a third microlens allowing light toenter a fourth photoelectric converting region of the fourth sub-pixel,and the lens part is structured such that an optical center of the firstmicrolens is positioned at least in a center region of a boundary regionbetween the first photoelectric converting region of the first sub-pixeland the third photoelectric converting region of the third sub-pixel, orwherein the lens part includes: a first microlens allowing light toenter a third photoelectric converting region of the third sub-pixel anda fourth photoelectric converting region of the fourth sub-pixel; asecond microlens allowing light to enter a first photoelectricconverting region of the first sub-pixel; and a third microlens allowinglight to enter a second photoelectric converting region of the secondsub-pixel, and the lens part is structured such that an optical centerof the first microlens is positioned at least in a center region of aboundary region between the third photoelectric converting region of thethird sub-pixel and the fourth photoelectric converting region of thefourth sub-pixel, or wherein the lens part includes: a first microlensallowing light to enter a second photoelectric converting region of thesecond sub-pixel and a fourth photoelectric converting region of thefourth sub-pixel; a second microlens allowing light to enter a firstphotoelectric converting region of the first sub-pixel; and a thirdmicrolens allowing light to enter a third photoelectric convertingregion of the third sub-pixel, and the lens part is structured such thatan optical center of the first microlens is positioned at least in acenter region of a boundary region between the second photoelectricconverting region of the second sub-pixel and the fourth photoelectricconverting region of the fourth sub-pixel.
 11. The solid-state imagingdevice according to claim 1, wherein, in the multi-pixel, a firstsub-pixel, a second sub-pixel, a third sub-pixel and a fourth sub-pixelare arranged in a square geometry such that, in a first direction, thefirst sub-pixel is adjacent to the second sub-pixel and the thirdsub-pixel is adjacent to the fourth sub-pixel and that, in a seconddirection orthogonal to the first direction, the first sub-pixel isadjacent to the third sub-pixel and the second sub-pixel is adjacent tothe fourth sub-pixel, and wherein the lens part includes: a firstmicrolens allowing light to enter a first photoelectric convertingregion of the first sub-pixel and a second photoelectric convertingregion of the second sub-pixel; and a second microlens allowing light toenter a third photoelectric converting region of the third sub-pixel anda fourth photoelectric converting region of the fourth sub-pixel, andthe lens part is structured such that an optical center of the firstmicrolens is positioned at least in a center region of a boundary regionbetween the first photoelectric converting region of the first sub-pixeland the second photoelectric converting region of the second sub-pixeland such that an optical center of the second microlens is positioned atleast in a center region of a boundary region between the thirdphotoelectric converting region of the third sub-pixel and the fourthphotoelectric converting region of the fourth sub-pixel, or wherein thelens part includes: a first microlens allowing light to enter a firstphotoelectric converting region of the first sub-pixel and a thirdphotoelectric converting region of the third sub-pixel; and a secondmicrolens allowing light to enter a second photoelectric convertingregion of the second sub-pixel and a fourth photoelectric convertingregion of the fourth sub-pixel, and the lens part is structured suchthat an optical center of the first microlens is positioned at least ina center region of a boundary region between the first photoelectricconverting region of the first sub-pixel and the third photoelectricconverting region of the third sub-pixel and such that an optical centerof the second microlens is positioned at least in a center region of aboundary region between the second photoelectric converting region ofthe second sub-pixel and the fourth photoelectric converting region ofthe fourth sub-pixel.
 12. A method for manufacturing a solid-stateimaging device, the solid-state imaging device including a multi-pixelhaving at least two sub-pixels, each sub-pixel having a photoelectricconverting region, the multi-pixel having: a back side separating partseparating a plurality of adjacent sub-pixels from each other at leastin a light entering portion of the photoelectric converting regionthereof; and a single lens part allowing light to enter thephotoelectric converting region of at least two of the sub-pixels,wherein an optical center of the lens part is positioned at a locationwhere the back side separating part is formed, and wherein the back sideseparating part is formed such that at least an optical center regionthereof exhibits lower reflection than the other region of the back sideseparating part.
 13. An electronic apparatus comprising: a solid-stateimaging device; and an optical system for forming a subject image on thesolid-state imaging device, wherein the solid-state imaging deviceincludes a multi-pixel having at least two sub-pixels, each sub-pixelhaving a photoelectric converting region, wherein the multi-pixel has: aback side separating part separating a plurality of adjacent sub-pixelsfrom each other at least in a light entering portion of thephotoelectric converting region; and a single lens part allowing lightto enter the photoelectric converting region of at least two of thesub-pixels, wherein the lens part is arranged such that an opticalcenter thereof is positioned at a location where the back sideseparating part is formed, and wherein the back side separating part isformed such that at least an optical center region thereof exhibitslower reflection than the other region of the back side separating part.